The objective of the proposed reseach is to define and characterize sterol synthesis and metabolism in fungi and to ascertain and study cellular reactions that are unique to the fungi and are of potential value in the control of these organisms in mycotic infections. Substantial evidence has been obtained which suggest that several key reactions in fungal sterol metabolism may be valuable in such control. The overall effect of sterol analogs, inhibitors, and mutations in sterol formation will be studied to determine their effects on a variety of reactions and fungal types.